This invention relates generally to retaining wall blocks and retaining walls constructed from such blocks. In particular, this invention relates to a retaining wall block system that allows the construction of walls having a random natural appearance with varying block face sizes to create the appearance of a natural stone wall.
Retaining walls are used in various landscaping projects and are available in a wide variety of styles. Numerous methods and materials exist for the construction of retaining walls. Such methods include the use of natural stone, poured concrete, precast panels, masonry, and landscape timbers or railroad ties.
In recent years, segmental concrete retaining wall units, which are dry stacked (i.e., built without the use of mortar), have become widely accepted in the construction of retaining walls. An example of such a unit is described in U.S. Pat. No. Re 34,314, which issued to Forsberg (Forsberg ""314). Such retaining wall units have gained popularity because they are mass produced and, consequently, relatively inexpensive. They are structurally sound, easy and relatively inexpensive to install, and couple the durability of concrete with the attractiveness of various architectural finishes. The retaining wall system described in Forsberg ""314 has been particularly successful because of its use of a block design that includes, among other design elements, a unique pinning system that interlocks and aligns the retaining wall units, thereby providing structural strength and allowing efficient installation. This system is advantageous in the construction of larger walls, when combined with the use of geogrids hooked over the pins, as described in U.S. Pat. No. 4,914,876 to Forsberg (""876).
The shape of the block is also an important feature during installation of a retaining wall. Forsberg ""876 illustrates a fairly complex shape for a retaining wall block which is particularly advantageous in the construction of curved walls. The block is symmetrical about a vertical plane which bisects the block at a midway point through the front and back faces.
Many commercially available blocks are symmetrical about a plane bisecting the front and back surfaces. Typically such blocks have planes rather than axes of symmetry, as there are differences between the top and bottom surfaces of such blocks. Clearly, blocks that are substantially square or rectangular (i.e., each surface being joined to another at an orthogonal angle) exhibit a great deal of symmetry. Other blocks are more complex in shape and exhibit only one vertical plane of symmetry. For example, U.S. Pat. No. 5,711,130 (Shatley) illustrates a block having substantially parallel front and back faces and non-parallel, mirror-image side wall surfaces. That is, there is a mirror plane of symmetry that vertically bisects the block. U.S. Pat. Nos. 5,598,679 (Orton et al.) and 5,294,216 (Sievert) illustrate a type of block having parallel front and back faces and non-parallel, converging side surfaces. The term xe2x80x9cconverging side surfacesxe2x80x9d means that the sides walls of the blocks converge as they approach the rear of the block. Such blocks are also symmetrical about a vertical plane that passes through the front and back surfaces.
There are advantages to having non-parallel surfaces on these blocks when constructing a retaining wall. The angles formed by these side surfaces permits construction of curvilinear walls, and moreover, permit the amount of curvature to vary according to the terrain and desired appearance of the retaining wall.
Another important feature of retaining wall blocks is the appearance of the block. Blocks having angled or curved faces are well known in the art. Many manufacturers also vary the color and the texture or pattern on the front face of the block. It might be desirable for the face of the block to be smooth, serrated, or grooved or to have an aggregate appearance.
The look of weathered natural stone is very appealing for retaining walls. There are several methods in the art to produce concrete retaining wall blocks having an appearance that to varying degrees mimics the look of natural stone. One well known method is to split the block during the manufacturing process so that the front face of the block has a fractured concrete surface that looks like a natural split rock. This is done by forming a slab in a mold and providing one or more grooves in the slab to function as one or more splitting planes. The slab is then split apart to form two or more blocks.
Another method to create a weathered stone appearance is to tumble the blocks together with other blocks in a large rotating canister. The collisions of the blocks in the tumbler chips off random pieces of the blocks, rounding the edges and creating a look that can be quite close to the appearance of a natural stone. This is a labor intensive undertaking that also can result in undesirable damage to the blocks and high overall costs of production.
Another method to make naturally appearing blocks has been described in U.S. Pat. Nos. 5,078,940 and 5,217,630 (both to Sayles). These patents describe a method and an apparatus for manufacturing a concrete block having an irregular surface. The irregular surface can be made to look similar to split stone, and thus is very desirable. This is done by pouring uncured block material into a mold cavity and causing a portion of the material to be retained in place relative to the cavity walls when the block is removed from the cavity. This results in a split appearance for the surface, without having to perform the splitting operation. This is an advantage because the expense and time of conventional block splitting is avoided.
Typically, retaining wall blocks are manufactured to have the desired appearance on the front face (i.e., the outer face of a wall) only. In the patents described above, the pattern or design is typically provided only to the front face because that is the only portion of the retaining wall block that is visible after the wall is constructed. Sometimes a portion of a side surface may be provided with a desired pattern or texture. In the Sayles patents described above, a natural or split look is obtained for only the front face. Such blocks do not allow the user the option to use either the front, side, or back faces of the block interchangeablity as the exposed xe2x80x9cfront facexe2x80x9d. To create a wall block that has a roughened texture on the front, side and back surfaces poses certain problems. If a splitting method is used, multiple splits and two orientations for the splits are required to create a quadrilateral block with texture on three sides. If a tumbling method is used, substantial portions of the block faces will be smooth and not entirely natural looking. Tumbling also is an expensive production method. If the method combines splitting and tumbling, the cost of production increases to a point where the end cost to the consumer is very high.
Creating a random, or ashlar, pattern in the face of a retaining wall is highly desirable. This gives the appearance of a mortared or dry-stacked natural stone wall, which is a traditional and well accepted look. Some current wall blocks are intended to create an ashlar pattern. However, the creation of a truly random appearance requires the production of multiple block shapes for use in a single retaining wall. This is inefficient from a production standpoint because this requires multiple molds and more kinds of blocks to inventory. If only one face of the block is intended to be the front face, then the block system will suffer a trade-off between having enough face sizes to create a random, natural appearance and the cost and inefficiency of using multiple molds and creating multiple inventory items.
Because of the natural variation in size of the stones used in stone retaining walls, the wall surface has variations in depth from stone to stone. None of the prior art concrete segmental retaining wall blocks is capable of duplicating this effect due to their alignment and connection systems requiring uniform alignment of the blocks and their front faces. It would be desirable to produce a block that could have random variations in face depth while maintaining the structural integrity of the wall structure.
It would be desirable to provide a system of blocks for constructing a retaining wall that combines the ease of installation of modern segmental retaining walls with the attractive appearance of a natural stone wall composed of stones of varying sizes. The block system should be efficient to produce, require a minimal number of different block shapes and allow the construction of walls with 90 degree corners, and the construction of freestanding walls with a desirable natural appearance. It would also be desirable to provide a retaining wall system that allowed an aesthetically pleasing randomness of appearance by varying the amount the front faces of individual blocks project out from the face of the wall, so that certain blocks project slightly out and others are slightly recessed, at the wall builder""s option. Moreover, it would be desirable to provide a retaining wall block with a desirable weathered appearance on at least three sides that could be manufactured in a manner that minimizes the need for splitting or tumbling the block.
This invention is a system of blocks comprising blocks of different sizes that are configured to be compatible with each other in the construction of a retaining wall or free-standing wall. Each block has at least three faces which are textured in a manner resulting in the appearance of natural stone. The faces have varying sizes based on variations in width. The orientation of the faces may be reversed so that either the front or the back of the block may serve as an exposed face, to give the wall a pleasing random variation of the block sizes that creates the look of a natural stone wall. In a preferred embodiment, the wall blocks use an attachment system that allows a positive connection between courses of blocks, and which accommodates reversal in orientation of the blocks if desired. The attachment system also allows the individual blocks to be aligned with varying degrees of outward projection, to give the wall builder another means of introducing randomness to the appearance of the wall face. The blocks can be used to construct retaining walls, free-standing walls, or sharp corners (i.e., 90 degree angles) with a natural finish on all exposed sides. The block""s side surfaces are configured to accommodate the construction of a variety of retaining walls, including walls having convex or concave curves. Known soil reinforcement methods such as geogrids may readily accommodated by the wall system. The wall system is designed to be easy to install and structurally sound.
In one aspect, this invention is a wall block for use in forming a wall from multiple wall blocks, the wall having a front surface and a rear surface, the block comprising an upper surface spaced apart from a substantially parallel lower surface, thereby defining a block thickness; opposed and substantially parallel first and second faces, the first face having an area greater than the second face; opposed and nonparallel side surfaces, the first and second faces being orthogonal to one of the side surfaces, the first and second faces together with the upper, lower and side surfaces forming a block body; wherein the block body is configured such that when a wall is constructed from the blocks, the front surface of the wall is formed of the first faces of a portion of the multiple wall blocks and the second faces of others of the multiple wall blocks.
Preferably, the first face, the second face, and at least one side surface are textured in a manner resulting in the appearance of natural stone. The upper surface of the block may have first, second, and third pin-receiving apertures aligned along first, second, and third axes which are substantially perpendicular to the upper and lower surfaces, the third pin-receiving aperture being substantially equidistant between the first and second faces, the first pin-receiving aperture being between the first face and the third pin-receiving aperture and the second pin-receiving aperture being between the second face and the third pin-receiving aperture, the first, second, and third pin-receiving apertures being arranged in a row perpendicular to the first and second faces. Preferably, the first and second pin-receiving apertures are equidistant from the third pin-receiving aperture. The lower surface of the block may comprise a channel that is parallel to and equidistant from the first and second faces and the block may comprise a core extending the thickness of the block.
In a second aspect, this invention is a wall block system having at least three blocks, multiples of the three blocks being suitable for use in constructing a wall from multiple courses of the blocks stacked one upon the other, the wall having a front surface with an irregular block pattern, the wall block system comprising first, second, and third blocks, each block having a thickness, width and length, the width of each block being different; each block having an upper surface spaced apart from a substantially parallel lower surface, thereby defining the block thickness; each block having opposed and substantially parallel first and second faces, thereby defining the block length, the area of the first face being greater than the area of the second face; each block having opposed and non-parallel side surfaces, thereby defining the block width; the first, second, and third blocks being configured such that they are capable of being positioned when constructing the wall such that the front surface of the wall is comprised of the first faces of a plurality of the first, second, and third blocks and the second faces of a plurality of the first, second, and third blocks to thereby provide a front wall surface having an irregular block pattern. Preferably, the upper surface of each of the three blocks has first, second, and third pin receiving apertures aligned along first, second, and third axes which are substantially perpendicular to the upper and lower surfaces, the third pin receiving aperture being substantially equidistant between the first and second faces, the first pin receiving aperture being between the first face and the third pin receiving aperture and the second pin receiving aperture being between the second face and the third pin receiving aperture, the first, second, and third pin receiving apertures being arranged in a row perpendicular to the first and second faces. The wall block system also may comprise a plurality of pins, each pin having a head portion and a body portion, the pins being configured such that when a wall is constructed from the wall block system, the head portion is configured to be received within the channel of the lower surface of a block in a first course of the wall and the body portion is configured to be received in a pin-receiving aperture of a second block in a next lower course of the wall. If no setback between the courses is desired, the body portion of the pin is configured to be received in the third pin-receiving aperture. If setback between courses of the wall is desired, the body portion of the pin is configured to be received in the second pin receiving aperture of the second block if the second block is positioned such that its first face is part of the front surface of the wall and in the first pin receiving aperture of the second block if the second block is positioned such that its second face is part of the front surface of the wall. Preferably, the first and second pin-receiving apertures are equidistant from the third pin-receiving aperture.
In a third aspect, this invention is a wall having a front surface and a rear surface, the wall comprising: at least a first lower course and a second upper course, each course comprising a plurality of blocks; each block having an upper surface spaced apart from a substantially parallel lower surface, thereby defining a block thickness; each block having opposed and substantially parallel first and second faces, the first face having an area greater than the second face; each block having opposed and non-parallel side surfaces, the first and second faces being orthogonal to one of the side surfaces, the first and second faces together with the upper, lower and side surfaces forming a block body; the blocks being positioned in the courses such that the front surface of the wall comprises the first faces of a plurality of the blocks and the second faces of a plurality of the blocks to thereby provide an irregular block pattern. Preferably, the blocks in each course comprise first, second, and third blocks, the widths of the first, second, and third blocks being different, the blocks being positioned in the courses such that the front surface of the wall is comprised of the first faces of a plurality of the first, second and third blocks and the second faces of a plurality of the first, second, and third blocks.
In a fourth aspect, this invention is a wall having a front surface and a rear surface, the wall comprising: at least a first lower course and a second upper course, each course comprising a plurality of first, second, and third blocks; each block having an upper surface spaced apart from a substantially parallel lower surface, thereby defining a block thickness; each block having opposed and substantially parallel first and second faces, thereby defining a block length, the area of the first face being greater than the area of the second face; each block having opposed and non-parallel side surfaces, thereby defining a block width, the width of the first, second, and third blocks being different; the blocks being positioned in the courses such that the front surface of the wall is comprised of the first faces of a plurality of the first, second, and third blocks and a plurality of the second faces of the first, second, and third blocks to thereby provide an irregular block pattern. The wall may further comprise a plurality of pins, each pin having a head portion and a body portion, the head portion being configured to be received within the channel of the lower surface of a block in a first course of the wall and the body portion being configured to be received in a pin receiving aperture of a second block in a next lower course of the wall. When the front surface of the wall is substantially vertical, the body portion of the pin is configured to be received in the third pin receiving aperture.
In a fifth aspect, this invention is a wall block for use in forming a wall from multiple wall blocks, the wall having a front surface and a rear surface, the block comprising: an upper surface spaced apart from a substantially parallel lower surface, thereby defining a block thickness, the upper surface having first, second, and third pin receiving apertures aligned along first, second, and third axes which are substantially perpendicular to the upper and lower surfaces, the third pin receiving aperture being substantially equidistant between the first and second faces, the first pin receiving aperture being between the first face and the third pin receiving aperture and the second pin receiving aperture being between the second face and the third pin receiving aperture, the first, second, and third pin receiving apertures being arranged in a row perpendicular to the first and second faces; opposed and substantially parallel first and second faces; opposed and non-parallel side surfaces, the first and second faces together with the upper, lower and side surfaces forming a block body; and wherein the block body is configured such that when a wall is formed from the wall block, the front surface of the wall is formed of the first faces of a portion of the multiple wall blocks and the second faces of others of the multiple wall blocks.
In a sixth aspect, this invention is a method for constructing a wall from blocks laid in multiple courses, one upon the other, such that the wall has a front surface with an irregular block pattern, the method comprising: providing wall blocks described above, and laying the blocks in a first course of the wall and a second course of the wall such that the front surface of the wall is formed of the first faces of a plurality of the blocks and the second faces of a plurality of the blocks. Preferably the method includes providing blocks having an attachment system allowing blocks in one course to be attached to blocks in the next lower course. Substantially vertical walls or angled walls may be obtained.
In a seventh aspect, this invention is a method for constructing a wall from blocks laid in multiple courses, one upon the other, such that the wall has a front surface with an irregular block pattern, the method comprising: providing a wall block system which includes blocks as described above of at least three sizes including first, second, and third blocks, each block having a thickness, width and length, the width of each block being different; laying the first, second, and third blocks in the first and second courses such that the front surface of the wall is comprised of the first faces of a plurality of the first, second, and third blocks and the second faces of a plurality of the first, second, and third blocks to thereby provide a front wall surface having an irregular block pattern.